This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To study metabolism of purines in patients with hyperuricemia who have the Lesch-Nyhan syndrome and other disorders. To characterize variant HGPRT enzymes, genes and the phenotypes of patients in whom they are found. To characterize the nature of metabolic abnormality and its molecular site in patients with hyperuricemias other than those involving HGPRT and to study transmission of Lesch-Nyhan syndrome and the mutation rate for x-linked lethal gene using heterozygote detection.